Home > > Cattle on digital power supply design and implementation of technical problems

Cattle on digital power supply design and implementation of technical problems 2012-01-31

First, what is digital power, analog power supply with the most essential difference?I think that the so-called digital power of nature is the power of the output current / voltage PWM regulation is the number of chips according to a certain number of control methods and algorithms, and this is the digital power of the most essential features. That extends the 8-bit, 16-bit microcontroller to provide a digital input and output interface, remote communication interface, but the power of the PWM modulation analog power supply regulation is dependent on the chip's power, only that they had a long face of digital power, but no digital power of the "core."Second, the digital power to achieve what the technical bottleneck?I believe that the current power is still present high-speed digital / high-resolution ADC technical problems (digital power feedback input); high speed / high precision power supply PID regulation or other algorithm of the PWM regulator; high speed / high precision PWM output problems (digital power DAC output).Many of the 32-bit DSP / ARM on-chip high-speed 10-bit, 12 bit ADC, ADC acquisition can be used as a high-speed high-frequency switching power supply, but the signal input range is typically 0 ~ 3.0/3.3V, industrial field the usual analog input range a positive and negative 10V does not have any DSP or ARM chip ADC can be resolved only by adding the outer end of the signal conditioning circuit. ADI, a few well-known manufacturers of analog catalog although fully consistent with high-speed, high precision (16bit ~ 18bit), the input signal range of ± 5V to ± 10V ADC products, but rarely seen in China, successful product application records, the issue of which I am afraid only of these devices are debugging engineers heart clear.High-precision PID controller or other algorithms power the PWM regulator in the popular 32-bit DSP or ARM processor seems not a problem, but if you want to add high-speed word, many software engineers would probably frown up. The field of motion control of TI TMS320F2812 rising star, for example, if the power supply switching frequency of 300KHz, the system in the 150MHz frequency, leaving the software engineer's task is 500 DSP instruction cycles to complete the ADC input data processing, power PID regulation, and function of the most demanding real-time tasks. If you want to avoid the cycle of power electronic devices in the open / shut-off caused by harmonics, ADC launched in the middle of the sampling device, then using UP-DOWN counter means counting the value of the count cycle synchronized to trigger the ADC sampling at this time the software engineers can use DSP instruction cycle only 250 of the poor, power PWM regulation is a difficult task!If the ADC problem can be extended outside the high-speed, high-precision devices to solve, you can use higher power PWM adjustable speed DSP / ARM / FPGA to complete, then the final high-speed / high precision PWM output problem, is to distinguish high-speed digital PWM rate problem, it can only rely on to provide DSP / ARM / FPGA of the big international companies solved. In fact, the resolution of digital PWM switching power supply is not a problem in the low frequency range (which is TI's C28X DSP in motor, inverter and other popular areas is an important reason); But in the high-frequency switching power supply, or high-precision power supply field, the problem becomes immediately highlighted. Why high-frequency, high-precision digital switching power supply is still a domestic blank, we use digital PWM resolution will calculate the formula is clear.